Fuel supply process for internal combustion engines



April 18, 1933. F. ROCHEFOR1 ,9

FUEL SUPPLY PROCESS FOR INTERNAL COMBUSTION ENGINES Filed Jan. 8, 1929' z'sheets-sheet 1 April 18, 1933. F. ROCHEFORT l;903,851

FUEL SUPPLY PROCESS FOR INTERNAL COMBUSTION ENGINES Filed J 8, 1929 2 Sheets-Sheet 2 Patented Apr. 18, 1933 UNITED STATES PATENT OFFICE FRANCOIS BOCHEFOBT, 01 PARIS, FRANCE FUEL SUPPLY PBbGESS F. INTERNAL COMBUSTION ENGINES Application filed January 8, 1928, Serial No. 831,086, and in France Bay 81, 1928.

The present invention relates to the direct feeding with fuel of internal combustion en-' gines in general, and more particularly of, engines operating on the constant volume cy- 5 cle and in which the charge of fuel is introtion with the injection atomizer or atomizers.

This process and this device are particularly suitab'e for engines in which the charge of fuel is introduced into the cylinder, after the end of theperiod'of admission of pure air,

by the aid'of a mass of carburetted gas, drawn oil from the engine during the previous compression stroke or strokes (see the French Patent No. 630,487 filedin the same name on June 3d, 1926). The process according to the invention consists in the fact that whenone cylinder is completely filled with air and when the air admission ports are closed, it receives a charge of rich carburetted mixture, which is compressed by the piston and is delivered in part into one or more other cylinders by way of a common capacity, after which the cylinder is completely cut oil and the ignition takes lace. The charge of rich mixture, admi into 0 a cylinder at the beginning of the compres-,

sion. is derived in part from the admission of fuel proper to this cylinder and in part from the admission of a charge of mixture derived from another cylinder by way, of the common capacity.

After some revolutions of the crank shaft,

nothing is "drawn oil from the volume of airadmitted, to the cylinder; each working cylinder is fully charged, then when it is hermetically closed it receives a charge of rich mixture, which it returns normally carburetted into anothercylinder; the operation consists then in an exchange of gaseous masses of different richness.

As there isintroduced into the cylinder a charge alreadypreviously carburetted, in another cylinder, it is only necessary to atomize forthe feed ng of the cylinder in question a quantity of fuel smaler than if pure air were injected instead of a carburetted mixture.

The introduction, from the beginning of the injection into the cylinder, of a gaseous mass already carburetted, greatly facilitates the utilization'of electric lgnition, by high tension sparking plugs, for igniting heavy nonvolatile products (heavy'oils).

The device according to the invention is characterized by a piston-valve operated so as to offer a large cross-section of passage for the delivery of the carburetted mixture from one cylinder into another or into other cylinders, by way of the common capacity and to ofi'er a reduced cross-section of passage during the admission of the rich carburetted mixture into this cylinder, in such a way as to ensure the atomization and the mixing up of the fuel introduced.

Upon the accompanying drawings: Figure 1 is a view in axial vertical section with certain parts half in external view;

Figure 2 is a view in vertical section, at right angles compared with the previous, with certain parts likewise in external view; this figure 2 represents a position of the pistonvalve slightly difierent from that of Figure 1 Figure 3 represents a detail, corresponding to a part of the-piston-valve. k

' Figures 3a and 3b are horizontalsections along the lines 3a-3a tively of Figure 3. i

'Figure 4 is a more or less diagrammatic plan view and 1 Figure 5 a view in vertical section along the line 55 of Figure 4, showing the appli-' cation of the invention to a four-cylinder engine operating on the two-stroke cycle.

Upon the block of cylinders a there is mounted anatomizer body p constituted by a mass of metal which is a good conductonof 4 heat and sufliciently insulated from the cylinder'block a by a gasket a which is a bad conductor of heat, in order tomaintain this at- 1 and 2).

A piston valve 0 comprising two diameters is mounted in such a way as to be able to receive a reciprocating vertical movement in the atomizer body p. The lower .part of the 100 j piston constitutes the cylindrical valve v and 3b-3b resp'ecso entered into a corresponding cylindrical recess p formed in the body of atomizer; in this 'part a: are formed calibrated convergent-divergent nozzles 12 spaced uniformly 5 around the vertical axis of this piston (Figure 3b) The central partof the piston valve comprises at its periphery helicoidal grooves o intended to communicate to the gaseous current a movement of gyration above the 10 nozzles b, at the moment of the injection into the engine cylinder (Figures 3 and 3a) The upper part of the piston is provided with packing rings v. This part is hollowed out at '0 in such a way as to serve as guide to a return spring (1 operating upon a hollow annular member (1, fitted into the atomizer body 12 and constituting the fuel admission valve. The space internal of this annular member (1 constitutes a mixing chamber 0. An annular groove 0 7 formed in the piston-valve body constitutes with the wall of the atomizer 12 another annular mixing chamber, separating the helicoidal grooves 12 from the nozzles b in order to permit suitable feeding of these nozzles.

In the interior of the piston-valve 'v and on the axis of the latter there is fitted with easy friction the stem 8 of a poppet valve 8, controlling the communication between the combustion chamber m of the cylinder and the capacity in which the piston-valve moves. This Stem 8 of the valve sis screwed at its upper end upon a cross-bar t which rests upon two springs 25 centred upon abutments t, which arrest upwards by their upper edge the piston-valve 'b in its upward movement, after this piston-valve is rendered free by the cams 70 arranged symmetrically on either side of a central cam 7: designed to control the poppet valve 8. These cams k and k are set at a given angle apart upon the common shaft k which bears them, the cam is being arranged in front in the direction of rotation as compared with the cam 11 (see the arrow in Figure 1).

Ports 0 and o of suitable cross sections are formed on one hand in the annular valve (1 and on the other hand in the atomizer body 17, in order to place the mixing chamber 0 in constant communication with the collector or collectors e (Figure 4) connecting all the feed devices of a single row of cylinders. The collector or collectors 0 may be surrounded by an insulating heat-retaining casing, or by a re-heating chamber, in which hot exhaust gases may circulate, with a limited flow, as represented at e in Figure 4. p v

In the body p of the atomizer there is provided a connection It for the supply of oil under presure, from which a channel h conducts the lubricant to a circular groove h, formed on the piston-valve '0 above the packmg rings 1); through passages h h h, and

through grooves it formed on the stem 8 of the valves 8, the oil under pressure is directed over the axial part of the guide of the stem of the poppet valve 8; this guide is constituted by the interior of the body of the piston-valve p and by the sleeve o fitted thereto.

The lubricant employed for the pistonvalve 12 and the poppet-valve s has to provide for the gas-tightness of the poppetvalve stem; this lubricant must be of different origin from that of the fuel in order to prevent mixture; it may consist for example of castor oil, in the case where petroleum products are employed as fuel.

The fuel, distributed under pressure b the connection 1 provided in the body 0 the atomizer p, is led tangentially by the channel Z to the circular groove Z formed in the body of the atomizer below the seating of the annular feed valve 03. Fine circular grooves l and helicoidal grooves Z formed at the periphery of the valve (Z, direct the liquid fuel, which would have a tendency to rise along the valve d, towards the mixing chamber 0, into which the helicoidal mixing passages '0 open.

A chamber 0 into which nozzles 6 open, is provided in the body of the atomizer 7), immediately above the injection and charge valve 8.

Figures 4 and 5 represent by way of example the application of the invention to an engine having four cylinders (1, 2, 3, 4,) operating according to the two-stroke cycle; it is to be understood that it is equally applicable to a four-stroke engine.

The ports represented at u are the apertures for the admission of pure air, which are closed with a certain lag by means of a driven distribution device (poppet-valve or slidevalve) after closure of the exhaust ports (not represented). These ports u are in communication [with a reservoir of air compressed to low-pressure or with a compressor, for the scavenging of the burnt gases and for the normal charging with pure air of the working cylinder.

The engine operating according to the twostroke cycle, the various phases of operation succeed from one cylinder to another at 90 interval, counted upon the circle of rotation of the crank shaft; the order of firing indicated by way of example is 1, 3, 2, 4. The admission of fuel to the atomizer takes place at the beginning of the period of injection into the working cylinder.

. The injection and charge valve 8 is opened progressively, immediately after the working piston 2 (Figure 5) has closed the ports u in its upward stroke (end of the admission of pure air to the cylinder and commencement of the compression phase).

As soon as the cylinder is hermetically closed (cylinder 3), the cam k acts upon the poppet-valve s by means of the cross bar t; this valve 8 opens. If'it be supposed that the crankshaft has already made several revolutions, there is some compressed gas in the collector c; this gas, assmg through the orts o and o, enters e hehcoidal channe s '0 formed on the piston-valve '0'; at this moment the fuel pump (not shown) delivers the charge of fuel .progressivley, so as to pro ect it in a thin horizontal layer, lifting by an infinitesimalamount the annular valve d subject to the tension of the spring d and to the pressure existing in the col ector e; a very rich carburetted mixture is created in the chamber a in the interior of the valve d; this mixture circulates rapidly in'the helicoidal grooves '0 surges into the mixing chamber 0 passes lence created b the pneumatic injection facilitates the mixture; the working plston z continuing ,to rise, there exists a very short time of balance of the, pressures between the pressure existing in the collector e and the 4 mixing chambers a c c and that existin in the compression chamber m of the cylin er;

afterwards the pressure becomes higher in the cylinder; there is produced a discharge of carburetted as into the collector e and into the mixing c ambers of the atomizers corresponding to the other cylinders; (in its upwards stroke, towards the end of the compression base, the piston thus serves as compressor, c arging the collector e and the mixmg chambers of the other atomizers) at this 7 moment the cams in, set rearward in relation to the cam is, engage the disc head 'v of the piston-valve '0; this piston-valve descends under the thrust of the cams; the fitted'portion 1: of the piston-valve in descending leaves its recess 11 in the body of the atomizer (as represented in Figure 2) and uncovers a cross-section of annular passage waysuflicient to feed the helicoidal grooves '0 and to charge the collector c; this cross-section is thus added to that of the nozzles b, which is too small to allow of conveniently charging the collector at high speeds of rotation of the en gme- Upon Fi re 5 there are shown three'lines: 5 T e full no I indicates the top dead centre, at the end of the compression stroke of the piston z. I v I The dot and dash line II indicates the point of ignition, about 20 to 25 degrees before the end of the com res'sion stroke. g The dotted ine III indicates the point of closure of the poppet valve a, slightly before the point of ignition, so as to obtain in the collector a charging pressure as near as possii gme. ,ble to the final efiective compression pressure. The average maximum pressure attained When the working piston reaches (the line) III, that is to say at a point very near the point ofignition, the poppet valve 8 is closedrapidly b its two return springs t acting beneath t e crossbar t after the passage of the cam is; after complete closure of the poppet valve 8, the piston-valve v slowly resumes its initial position of rest, this closed and is receiving a charge of rich mixture, injected and difi'used into the pure air contained in the working cylinder; carburetion is facilitated by the turbulence created by the end of the scavenging and charging. period, as well as by the momentum of the gas injected.

Continuing its upward stroke, the piston of the cylinder 3 will pass through the moment 0 balance of pressures between the pressure existing in the collector e and that existing in the cylinder; the poppet-valves of the injector of cylinder 1 is closed, the piston of this cylinder 1 reaching the ignition point; the injector valve of the cylinder 2 is about to open, assoon as the iston of this cylinder 2 has again covered t e air admission ports u (in its upward stroke, at the beginning of the compression phase in this cylinder 2) at this moment, the cylinder 3 will charge the collector c with a mass of car-. buretted gas; "thereafter the po pet valve 8 of the in ector-of cylinder 31W! close and that of the injector of cylinder 4 will open;

the cylinder 2 in its turn will serve as compressor; the valve, 8 of the injector of cylinder 2 will close, and the valve 0 of the injector of cylinder-1 will open, the cylinder 4 serving as compressor for it, and so on; -4 the cycle is repeated, the phases of injection into the cylinders crossing continually with the phases of charging the collector e, in such a way as to obtain-an average quality of car- I buretted mixture, admitted into the cylinders, as well as a balancing o f compression.

It iseasy to understand that if any one cylinder receives a richer charge of mixture than that admitted into the adjacent cylinder, at the moment of the injection, a portion of this mixture being withdrawn before combustion in order to as to another cylinder,

and this operation eing repeated from one cylinder to another, immediately after each injection andbefore combustion, an average is established in the richness of the-mixture, admitted to the'difleren't cylinders of the enin the collector e is equal to that existing in the working cylinders, at the moment of closure of the atomizer poppet-valve s.

The collector e being charged with carburetted gases carried by compression to a certain temperature, itis necessary to maintain this temperature approximately constant throughout the passages and the injector bodies. For this purpose the injector bodies, as well as the collector or collectors connecting them together, are constructed of a metal which is a good conductor of heat.

The collector e and the injector-atomizer bodies ;0 may be insulated from the outer air, as indicated above. by a chamber in which there circulate hot gases derived from the exhaust of the cylinders, but of limited flow, in such a way as never toattain in the injectors and in the collector the temperature .of spontaneous ignition of the mixture carburcttcd and compressed in these capacities.

There may be provided a simple lagging cover insulating the Walls from external radiation, or else heating by electrical resistance,

around upon aframe which is a good conductor of heat, covering the wall of the collector, this resistance receiving a low tension current furnished by battery or generator.

If it is desired to increase considerably the speeds of rotation of the engine, while yet utilizing heavy fuels, there may be incorporated a special mixture or gas, in order to render the combustion more rapid, by the aidof an auxiliary compressor of small output delivering this mixture into the collector e and into the mixing chambers of the atomizers.

The invention is applicable to the utilization in engines of heavy liquid fuels, such as alcohol, petroleum, gas oil, fuel oil, vegetable oils, etc., of low volatility, as well as to volatile fuels such as benzol, petrol, etc.; the process and the device according to the invention may likewise be employed for the feeding of engines with gaseous fuels, for example town gas or any other combustible gas.

It is to be noted that in order to obtain a satisfactory atomization of heavy fuels, it is absolutely necessary to have very high speeds of flow of the fluid acting as mechanical and physical agent, in order to obtain satisfactory sub-division and even distribution of this fuel in the pure air of the 'working cylinder; this leads to the utilization of small cross-sections of passage for the injection of the gases from the collector into the cylinder; for this purpose the'passige is determined solely by the nozzles b, the valve 12 of the piston-valve '0 being at thisphase of the cycle entered into its recess 7 formed in the body p of the atomizer. On the other hand, in order to facilitate rapid charging and to as high a pressure as possible, it is necessary to reduce the resistances to the flow of the gases delivered by the working piston into the collector e at the end of the com pression; for this purpose the poppet-valve 8 remains fully open and the valve 0 oper ated by the cams leaves its recess p in such a way as to add a large annular cross-sec tion of passage to that already furnished by the nozzles 6 (see Figure 2). The interruption of the communication between the cylinder and the collector e is effected by the closure of the poppet-valve s at the point 111; the piston valve '0 and its valve '0 slowly resume their initial position in order to obviate shocks upon the abutments t The device according to the invention presents moreover the following advantages: it protects against the harmful effects of combustion the calibrated passages or nozzles serving to regulate the speed of flow of the gases during the injection phase.

All the atomizers of a single row of cylinders are connected together, utilizing for the charging of the collector as well as for the injection into the cylinders the same pipes reducedv to the shortest possible length.

The number of gas-tight parts (poppet valves) in connection with the combustion chamber or chambers of the engine is reduced to the minimum.

A very active circulation is created in the mixing chambers and passages, in order to attenuate as much as possible the condensatiog of the fuel already atomized or vaporize An active turbulence is produced above the nozzles, during the phase of injection into the working cylinder.

The temperature is regularized over all the atomizers, by the use in their construction as well as for that of the collector or collectors, of metals which are good conductors of heat.

It is evident that the construction of the atomizer might be modified, without changmg in any way the system of operation in relation to the engine.

There might likewise be utilized the various poppet-valves or needle-valves for injection described in the French Patents 'No. 563,174 dated 17th May, 1922, No. 572,753

dated January 9th, 1923, and No. 575,102

dated December 28th, 1923, filed in the same name.

There might likewise be utilized rotary distributing devices instead and in place of the reciprocating distribution members (piston-valve o v v and poppet-valves s) without changing in any wav the process of feeding. 7

Likewise the collector or.collectors might be charged by a distributing device (poppetvalve, valve, reciprocating or rotary slide valve) separate from the atomizer and in communication with the interior of the cylinder; in this way, the benefits of the grouping, the efiiciency and the security would be lost,

the cylinders, passage means constantly connecting the common capacity with each of said valve chambers, passage means adapted to connect each valve chamber with its respective cylinder, means for supplying fuel sander pressure to'each of said valve chambers, and in each of. said valve chambers valve means adapted to'ensure a thoroughmixing of the said fuel and of the normally carburetted charge, admitted from the common capacity in each of said valve chambers to produce a rich carburetted mixture in the same, means for controlling the passage means between each valve chamber and its respective cylinder to allow the flow of a part of the normally carburetted charge from each 'cylinder about the end of the compression stroke therein through the respective valve chamber to the common capacity, and inversely, the flow of the rich carburetted mixture from each valve chamber into the respective cylinder at the beginning of the next compression stroke therein.

2. Aninternal combustion engine comprising a plurality of cylinders, a piston operating in .each of said cylinders, a capacity common to all of said cylinders and adapted to be supplied with a part of the normally carburetted charge from the cylinders about the end of the compression stroke in each of them, a valve chamber arranged on each of the cylinders, passage means constantly connecting the common capacity with each of said valve chamhers, passage means adapted to connect each valve chamber with its respective cylinder, means for supplyin fuel under pressure to each of said valve 0 ambers, and in each of said valve chambers valve means ada ted to ensure a thorough mixing of the sald fuel vand of the normally carburetted charge ad-' mitted from the common capacity in each of said valve chambers to produce a rich carburetted mixture in the same, means for controlling the passage means between each valve chamber and its respective cylinder to .allow the How through a large cross sectional area of passage of a part of the normally carburetted charge from each cylinder, about the end of the compression stroke-therein each valve chamberinto the respective cylinder at the beginning of the next compression stroke therein. f a

.3. An internal combustion engine comprising a plurality of cylinders, a piston operating in each of said cylinders, a capacity come monto all of said cylinders and adapted to be supplied with a part of the normally carburetted charge from the cylinders about the end of the compression stroke in each of them, a valve chamber arranged on each of the cylinders, passage means constantly connecting the common capacity with each of said valve chambers, passage means adapted to connect each valve chamber with its respective cylinder, means for supplying fuel under pressure to each of said valve chambers, and in each of said valve chambers valve means adapted to ensure a thorough mixing of the saidfuel and of the normally carburetted charge admitted from the common capacity in each of said valve chambers, to produce a rich carburetted mixture in the same, means for controlling the passage means between each valve chamber and its respective cylinder to allow the flow of a part of the normally carburetted charge from each cylinder about the end of the compression stroke therein through the respective valve chamber to the common capacity, and inversely, the flow of the rich carburetted mixture from each valve chamber into the respective cylinder at the beginning of the next compression stroke therein, together with means or maintaining the carburetted spontaneous ignition of said mixture.

In testimony whereof I have signed this specification. I

FRANQOIS. ROCHEFORTI through the respective valve chamber to the common capacity, and inversely, the flow through a small cross sectional area offpassage, of the rich carburettedmixture cm 

